Presenter(s): Haley Faringer − Environmental Science
Co Presenter(s): Rulon Hardy, Christina Ellison
Faculty Mentor(s): Richard Emlet, Jan Hodder
Poster 60
Research Area: Natural/Physical Science, Marine Biology, Ecology
Scarus iseri, the striped parrotfish, is among the most abundant parrotfish on Caribbean coral reefs. As grazing herbivores, they shape community structure by transmitting primary production up the food chain, regulating algal biomass, and facilitating benthic settlers in the process of removing patches of algae. S. iseri are protogynous hermaphrodites with 3 life stages (juvenile, initial and terminal) identifiable in the field. Our study investigates differences in range size, habitat utilization, and behavior between the juvenile and terminal phases. Through this research, we hoped to gain a better understanding of how these fish utilize their habitat as they grow, and how resources are partitioned among members of a population.
Our research was conducted at House Reef, near the Smithsonian’s Tropical Research Institute in Bocas del Toro, Panama. We followed 6 focal individuals of each life stage for a 15-minute period to establish their range. These parameters were chosen due to time constraints of the study period. We only had 4 days to complete the research, including data analysis, and wanted to maximize both the amount of time we followed each fish, and the number of replicates for each life stage. The numbers we chose reflect a compromise between these two variables. Using survey flags and transect-tape, we calculated the area of each range and drew a map of its shape.
Before conducting surveys in the field, we constructed an ethogram, or a table of observed behaviors for the fish. Then for 5 minutes of the 15-minute period we observed and recorded behaviors of the fish according to our ethogram. This allowed us to gain insight about feeding frequency, substrate used for feeding (e.g. sediment, sponge, sand, etc.), the proportion of each type of substrate used, and social behavior within a population.
Our results suggest that range size increases with more advanced life stage. Time allocations for feeding and non-feeding behaviors are similar between the two stages and both life stages utilize the same substrate types for feeding, in similar proportions. Juveniles frequently form groups, while terminal phase individuals are often found alone.
Because Scarus iseri is so prominent in the Caribbean Ocean, it has an increased ability to transfer nutrients through trophic levels. Not only is it important to understand how resource utilization within this species is affected by life stage, but how this resource utilization affects nutrient levels and habitat availability for other species on reefs of the Caribbean Ocean. With the recognition of variable social behaviors and range sizes between juveniles and terminal adults, we hope to better understand the nature of these fish’s relationship with each other and other stakeholders on the reef. The data collected is important because it can be used to inform the management of marine protected areas aimed at preserving this important group of fish.